Wireless networks continue to evolve as new communication technologies develop and standardize. Wireless network operators can deploy new communication technologies in parallel with earlier generation communication technologies, and wireless networks can support multiple communication technologies simultaneously to provide smooth transitions through multiple generations of mobile wireless devices. Mobile wireless devices can include hardware and software to support wireless connections to different types of wireless networks that use different wireless communication technologies. Wireless networks using different radio access technologies (RATs) can overlap in geographic area coverage, and mobile wireless devices can support connections using different RATs depending on services and/or coverage available. A wireless service provider can provide services to mobile wireless devices through overlapping wireless networks, and mobile wireless devices can connect to one or more of the overlapping wireless networks. In a representative embodiment, a wireless service provider and/or a mobile wireless device can include simultaneous support for a Third Generation Partnership Project (3GPP) Long Term Evolution (LTE) wireless communication protocol and a “legacy” third generation (and/or earlier generation) wireless communication protocol. Representative “legacy” protocols include the Third Generation Partnership Project 2 (3GPP2) Code Division Multiple Access (CDMA) 2000 1× (also referred to as 1×RTT or 1×) wireless communication protocol, the 3GPP Universal Mobile Telecommunications System (UMTS) wireless communication protocol, and the 3GPP Global System for Mobile Communications (GSM) wireless communication protocol.
A dual network mobile wireless device that includes support for both CDMA 2000 1× and LTE is described as a representative device herein. The same teachings, however, can be applied to other mobile wireless devices that can operate in dual (or more generally multiple) wireless networks that use different radio access technologies. In particular, the teachings disclosed herein can pertain to mobile wireless devices that switch wireless circuitry contained therein from one wireless radio access technology to another wireless radio access technology and back again. The teachings provided herein apply to mobile wireless devices that interrupt transmission and/or reception between the mobile wireless device and a first wireless access network for an extended period of time, e.g., to transmit and/or receive on a second wireless access network, and upon return to the first wireless access network determine a connection state for a radio resource control (RRC) connection between the mobile wireless communication device and the first wireless access network.
Dual radio mobile wireless devices can include separate sets of wireless circuitry for each wireless communication protocol, such as a first wireless circuitry to support connections with a CDMA 2000 1× wireless network and a second wireless circuitry to support connections with an LTE wireless network. In particular, in a dual radio mobile wireless device, each wireless circuitry can include its own receive signal processing chain, including in some instances multiple receive antennas and attendant signal processing blocks for each wireless circuitry for a given radio access technology. With separate radio frequency receive signaling chains available to each wireless circuitry in the dual radio mobile wireless device, paging messages can be received independently from two different wireless networks, such as from the CDMA 2000 1× wireless network and from the LTE wireless network, by the dual radio mobile wireless device. Even when the dual radio mobile wireless device is connected and actively transferring data using one wireless circuitry to one of the wireless networks, such as the LTE wireless network, the dual radio mobile wireless device can also listen for and receive a paging message through the other parallel wireless circuitry from a second wireless access network, such as the CDMA 2000 1× wireless network. Thus, the dual radio mobile wireless device can establish a mobile device originating or mobile device terminating circuit switched voice connection through the CDMA 2000 1× wireless network while also being actively connected to (or simultaneously camped on) a packet switched LTE wireless network. Dual radio mobile wireless devices, however, can consume more power, can require a larger physical form factor and can require additional components (and cost more) than a more integrated “single radio” mobile wireless device.
A single radio mobile wireless device, at least in some configurations, can include wireless circuitry that can support different wireless communications protocols but can be unable to be actively connected to a first wireless access network and to receive communication from a second wireless access network simultaneously. The single radio mobile wireless device can support multiple wireless communication technologies, such as connections to a CDMA 2000 1× wireless network and to an LTE wireless network, but only to one wireless network at any given time. The single radio mobile wireless device can be limited to receiving signals that use one wireless communication technology type at a time, particularly when multiple antennas are used to receive signals for a single communication technology that supports receive diversity. In some embodiments, the single radio mobile wireless device can include a single radio frequency receive signaling chain that can process one radio frequency technology at a time. In a representative embodiment, a single radio mobile wireless device is able to connect to or camp on an evolved Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (eUTRAN) of an LTE (or LTE-Advanced) wireless network and also to connect to or camp on a radio access network (RAN) of the CDMA 2000 1× wireless network, but not to both wireless networks simultaneously. The single radio mobile wireless device can be registered on both the LTE wireless network and on the CDMA 2000 1× wireless network and can therefore form connections with each wireless network singly but not simultaneously. The single radio mobile wireless device can be connected on the LTE wireless network and can interrupt the connection to the LTE wireless network to maintain registration on the CDMA 2000 1× wireless network. During the interrupted connection, control signaling and responses to received transmissions between the mobile wireless device and the wireless access network portion of the LTE wireless network can be interrupted. Packet transmissions and/or signaling messages from the LTE wireless network to the single radio mobile wireless device can be dropped. For sufficiently long interruptions, the LTE wireless network can drop a radio resource control (RRC) connection with the single radio mobile wireless device. Upon returning to the LTE wireless network from the CDMA 2000 1× wireless network, the mobile wireless device can assume the RRC connection with the LTE wireless network is still active, while the LTE wireless network can assume an “idle” connection state exists with the mobile wireless device.
This application describes methods by which a mobile wireless device can operate in a multiple wireless network environment and determine connections states after connection interruptions between the mobile wireless device and an access network portion of a wireless network.